Computer systems for large scale applications such as banking, insurance, and telephony are gaining popularity. These computer systems require a large amount of storage capacity for storing various types of critical data such as consumer details, billing records and so on. To provide data reliability and fault tolerance of the critical data, it is often necessary to implement data redundancy. One of the popular techniques to provide data redundancy implements multiple paths between a client and a storage device using a virtual input/output (I/O) environment.
Some of the currently available techniques for providing multiple paths between the client and the storage device enable simultaneous access to the storage device using a virtual I/O client partition through multiple virtual I/O server partitions. In such instances, the virtual I/O client partition may send a request to the storage device on all the virtual I/O server partitions. Upon receipt of such a request, one of the virtual I/O server partitions may respond and enable access to the storage device. However, these techniques require storage devices with multiple ports. Also, these techniques require redundant physical slots and physical storage device adapters for coupling the multiple-port storage device to the multiple virtual I/O server partitions. Hence, implementing these techniques is expensive. Furthermore, these techniques cannot be applied to storage devices that do not support simultaneous access from the multiple virtual I/O server partitions.
In other techniques for providing multiple paths between the client and the storage device, data is replicated or mirrored over multiple storage devices and each of the multiple storage devices is assigned to one of the multiple virtual I/O server partitions. The virtual I/O client partition then accesses these storage devices via the multiple virtual I/O server partitions. However, these techniques also need redundant physical storage devices and physical storage device adapters, thereby increasing the cost.
Therefore, there is a need in the art for a cost-effective technique for providing multiple paths for accessing the storage device that requires minimal physical resources.